Using rebuild with point editing of solids

Hello folks.
I have an ellipsoid I am point editing on.
I have rebuilt to establish edit points.
I’ve use a solid object (box) as a cutting tool to trim the lower half.
I rebuild again to change edit point quantity, and the ellipsoid gets redrawn to its original form.
Where am I going wrong here?
Thanks in advance…

after trimming use ShrinkTrimmedSrf to reduce the control point structure to the trimmed surface

Thanks Diego. I’m not really sure that’s the solution, but maybe I should describe the problem differently.
Probably a better question: if I use ‘insertkink’ to add a strip of control points, can I remove them later? Let’s say I want to fine-tune an edge.
I think I probably added too many control points previously with the rebuild command. Gotta resist doing that…

post a capture with what you have.

yes you can add or delete rows of points anytime.